# ODBC drivers in Polybase: Avoiding issues with NVARCHAR columns

**URL:** <https://community.cdata.com/t/odbc-drivers-in-polybase-avoiding-issues-with-nvarchar-columns/329>\
**Category:** Data Sources\
**Tags:** article, api-driver, polybase\
**Created:** [August 14, 2023, 6:13pm UTC](https://community.cdata.com/t/odbc-drivers-in-polybase-avoiding-issues-with-nvarchar-columns/329 "2023-08-14T18:13:52Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![LaurenH](https://avatars.discourse-cdn.com/v4/letter/l/ecae2f/32.png) [@LaurenH](https://community.cdata.com/u/LaurenH)\
**Post date:** [August 14, 2023, 6:13pm UTC](https://community.cdata.com/t/odbc-drivers-in-polybase-avoiding-issues-with-nvarchar-columns/329/1 "2023-08-14T18:13:52Z")

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Polybase has a maximum row size of 32 KB in SQL Server (or 1 MB in Azure Synapse Analytics). As a good rule of thumb, when creating NVARCHAR columns with the CREATE EXTERNAL TABLE statement, set the size to 255 unless you need more space. This will also help to make processing times faster and avoid using more resources than necessary.